Coinbase’s Base Supercharges Speed with Flashblocks on Testnet
Flashblocks is the latest technology from Coinbase”s Layer 2 blockchain, Base, which is breaking speed limits when it comes to transactions.
The technology, unveiled at ETHDenver 2025, reduces effective block time from 2 seconds to an astounding 200 milliseconds, tenfold scaling improvement aimed at boosting scalability and usability. The Flashblocks are available for testnet live now on the Base Sepolia testnet (currently streaming preconfirmation blocks every 200 milliseconds).
In addition to enabling early confirmations and built in revert protection, this approach accelerates transaction processing without introducing uncertainty in users or developers. If everything goes according to plan, the feature will gradually be rolled out onto Base’s mainnet in Q2 2025.
Base Expands DeFi Capabilities with Flashblocks
This speed boost is done in collaboration with Flashbots, a research group around Ethereum’s transaction ordering and MEV (Maximal Extractable Value) solutions. Base Uniswap were recently added to the list of DeFi projects implementing flashblocks to bring 0.25 second block times to its Layer 2 network, Unichain.
However, Base didn’t end with Flashblocks. The team also unveiled two additional innovations alongside it at ETHDenver, Base Appchains and Smart Wallet Sub Accounts.
Custom Scalability on Base Appchains are application specific blockchains that run on Base’s OP Stack powered Layer 2 framework. These are Layer 3 chains, or rollup rollups, with dedicated block space to reserve for high traffic apps. It is an attractive solution to scalability of complex applications because developers can override their chains with unique gas tokens and fee structures.
Base also introduced Smart Wallet Sub Accounts, a feature that makes managing multiple wallets on-chain much more simple. With a single interface, users will be able to monitor various wallets and they will be more efficient and less friction in the Web3 interaction.
Base is the most used Layer 2 chain on Ethereum and is pushing the envelope in blockchain innovation. At the front end, Coinbase will have Application Chains, Appchains, and Smart Wallet Sub Accounts in the pipeline all of which point towards, in 2025 and beyond, a remolded Layer 2 experience with the debut of Flashblocks on its network.
